I'm an undergraduate and I have a paper due tomorrow night. I have been doing research on the Aztec uses of their native wine, pulque, and its development through colonial times into the early modern era.
My research was going really well, until I found a paper that had been done on the exact same topic. It argues the same point as mine, and uses a lot of the same sources (some even more interesting ones).
I've been in the library for weeks working on this paper and I feel like all of my work has just been invalidated. I have research on a kind of tangential topic (the difference in agriculture techniques between Aztec botanical gardens and their farms) but I don't know if I can fit it in. I've let my professor know of my problem, hopefully granting me a small extension.
When a historian runs into a problem like this, what is the solution? Where can I start over from?
I admire your integrity, but I think you're way too worried. An undergraduate term paper is not expected to be original research. (A PhD candidate would spend a year at the least studying everything they could find on the topic, in the hope that they will be able to say something that hasn't been said before. No one expects this of you.) The point is the process of the research, which you seem to have done admirably well - too admirably well! Your professor should be very understanding. This is disappointing, but it's also a lesson well earned.
sowser has previously written an essay for the subreddit about originality in undergraduate research with contributions by /u/restricteddata and /u/sunagainstgold.